@banitama if already a CTO we can assume they're highly technical and analytical. Would it not be enough to tell your friend to take the time to read the actual "Bitcoin not blockchain" article and maybe even the entire series?
https://nakamotoinstitute.org/mempool/bitcoin-not-blockchain/
There's also the great "Why Bitcoin, Not Shitcoin" article.
@ugmug he want to “build blockchain project with real use cases” so I think it’s beneficial to have a chat with him first before sending articles.
I think a common pitfall for many technical people is the tendency to find a problem for a solution, and hopefully I can identify his problem first before moving on to bitcoin.